Both professional and amateur photographers are familiar with the problem of glare, which is a very harsh bright light that may cause regions of total or near-total overexposure in photographic images. Glare may occur due to light reflections from a wide variety of objects, including flat glass surfaces such as windows, mirrors, and aquariums, as well as eyeglasses, TV sets, moving water, chrome on cars, and facets on jewelry. Reflective items being photographed for auction purposes for example often require a surrounding diffuse lighting screen to allow clear photography. Glare may also be caused by very intense point-like light sources such as studio, theatrical, or stadium lights, the sun, and Christmas tree lights. Reflections and point-like light sources may also cause lens flare-related image artifacts, as is known in the art.
The light from a photographic flash reflecting back to the camera, typically very directly from flat surfaces, is however the most common cause of image glare. Amateur photographers in particular routinely have problems with flash-related artifacts in their images, especially when using a camera that has a fixed flash system near the lens. Underwater photography is particularly challenging because a flash is nearly always required.
Photographic flash systems may be used to successfully augment available light, but such use is not without complications, even for professionals. Flash-based image artifacts may not be noticed nor their impact on image quality fully appreciated at the time an image is taken. Getting the best overall exposure from the combination of available light and flash illumination is not always easy. As a result, photographers sometimes take bracketed images, wherein the exposure level for each image is varied both above and below a particular setting. The photographer must hope that one of the images will prove to be adequately lit overall and not marred by artifacts. Otherwise, the typical alternative is to painstakingly manually retouch photos, often using various software tools for assistance. Unfortunately, this practice may be very time intensive and may produce rather crude results. Therefore, detrimental image artifacts may discourage the use of flash systems, even with bracketing and software retouching.
As a result, there is a need for a tool to automatically remove glare artifacts from photographic images, particularly those pictures taken with a flash unit.